Question: As we merge sort the following, what will the array look like just before performing the last merge?
35 57 53 26 50 15 22 21 25 14 11 2
Answer: Mergesort splits the array into two pieces and recursively sorts both pieces. Finally it merges these two pieces and returns the resulting array. So just before this last merge it will have sorted these two equal-sized pieces.
15 26 35 50 53 57 2 11 14 21 22 25
In particular, the first six elements (the first half of the initial array) are sorted, and the last six elements (the second half of the initial array) are sorted.